1. Field of the Invention
The present invention relates to a semiconductor manufacturing system for treating exhaust gas containing an organic solvent, and a method of manufacturing a semiconductor device.
2. Background Art
During use of a conventional aligner that irradiates a semiconductor wafer with ultraviolet light or the like or a conventional inspection apparatus using light, siloxane in the atmosphere can adhere to a lens, a mirror or the like in the optical system, and SiO2 can be deposited, resulting in the so-called “haze”. The “haze” is disadvantageous because the aligner or the inspection apparatus is deteriorated in illuminance.
For example, hexadimethyldisilazane (HMDS) used in the lithography process is decomposed into ammonia and trimethylsilanol (TMS) (formula (1)), so that a low-molecular-weight siloxane is produced. An organic solvent or the like containing the low-molecular-weight siloxane and other kinds of siloxane becomes a cause of illuminance deterioration of the aligner and the inspection apparatus.Si(CH3)3—NH—Si(CH3)3+2H2O →NH3+2Si(CH3)3—OH   (1)
HMDS is used for a resist applying apparatus. The exhaust gas from the resist applying apparatus is fed to the scrubber of the building through the exhaust gas duct of the clean room and treated by the scrubber before being discharged to the outside.
However, the scrubber used for the entire clean room has a low removal efficiency because the amount of exhaust gas is high. Specifically, the TMS concentration at the exhaust gas outlet of the scrubber is on the order of several hundreds to several thousands ppb. The gas containing the remaining TMS is taken in and supplied into the clean room or to the aligner or the like in the clean room through the outside air inlet of the clean room.
The aligner or the like, which can be affected by TMS, has an activated carbon filter for removing TMS at the air inlet thereof. However, the outside air conditioner of the clean room removes TMS at a low removal efficiency because the flow rate to be processed is high. Thus, there is a problem that the life of the activated carbon filter is extremely short, the frequency of filter replacement is high, and therefore, the availability ratio of the aligner is low.
There has been proposed a semiconductor manufacturing apparatus (resist applying apparatus) that has a temperature/humidity adjusting unit that feeds air after adjusting the temperature and humidity thereof and treats a substrate with an organic solvent while flowing the adjusted air supplied from the temperature/humidity adjusting unit from an upper part of the apparatus (see Japanese Patent Laid-Open Publication No. 9-145112, for example).
The semiconductor manufacturing apparatus is sealed with a cover or the like covering the perimeter thereof, collects the adjusted air supplied from the temperature/humidity adjusting unit through a collecting port in the bottom of the cover with collecting means composed of an intake fan, piping and the like, and supplies the adjusted air to an adjustment part in the temperature/humidity adjusting unit to make the adjusted air circulate. Furthermore, the semiconductor manufacturing apparatus removes the organic solvent or particles in the collected adjusted air with an organic solvent removing part or a particle removing filter.
The arrangement described above can suppress corrosion of parts located in lower portions of the semiconductor manufacturing apparatus or an adverse effect on the human body, reduce the running cost, and reduce the turbulent flow between the apparatus and an adjacent apparatus.
However, the conventional technique neither involves treatment of the exhaust gas containing an organic solvent containing siloxane discharged to the outside of the clean room nor reduces the burden on the activated carbon filter installed in the aligner or the like described above.